Various styles of rigs have been proposed for utilizing both coiled tubing and threaded tubulars to be selectively inserted through the rig floor and into the well. Rigs conventionally include a mast extending upward from a rig base when in an operative position. Rigs sometimes referred to as universal rigs include both a coiled tubing injector supported on the mast to insert coiled tubing into the well, and a top drive movable along an axis of the mast when in the operative position to insert a threaded tubular into the well.
Rigs with coiled tubing injectors have traditionally relied primarily upon the use of the coiled tubing to conduct downhole operations. Coiled tubing is thus conventionally used to suspend a downhole motor in the well, with fluid pumped through the coiled tubing to drive the downhole motor and drill the well. Other operations may also be conducted with coiled tubing in a manner more efficient than if conducted with threaded tubulars. Top drives have also been provided on the mast of universal rigs for inserting a threaded tubular into a well, although typically top drives have been used to threadably connect sections of a bottom hole assembly or to run surface casing in the well, and generally have not been used to drill substantial portions of the well. Accordingly, when a plurality of tubular joints are run in or out of the well utilizing the top drive, the tubular joints are threadably connected or disconnected, and are pulled up or laid down on the rig floor through the V-door of the rig. This operation takes a considerable amount of time and is thus costly.
The disadvantages of the prior art are overcome by the present invention, and an improved rig is hereinafter disclosed for selectively inserting coiled tubing or threaded tubulars into a well.